MG 2.2 Thumbnails don't keep Transparency Data

[Venthas]

Thumbnails for media which contain transparent backgrounds (pngs, for example), aren't being displayed properly on any widget or area using a thumbnail.:

The content:


The thumbnail:

 

[Chris D]

We've seen this sporadically but nothing in the software has changed in this area for some time.

Our best guess currently is that there's a specific version of PHP or GD library that is bugged which causes this. Changing to a different PHP version may help.

 

[Venthas]

We went from php 7.4 to 7.3, and this has changed the transparencies on the thumbnails to just a white background.

 

[Chris D]

That sounds more acceptable.

That may, in fact, be intentional - we may not attempt to preserve the transparency. That looks consistent with the behaviour we're seeing here, if you take a look at our media index:



So what you're seeing in PHP 7.3 is the expected behaviour which does demonstrate that there may be an issue with the specific PHP 7.4 build or the specific version of the GD extension in use when you're using that PHP version.

FWIW I don't think this is a PHP 7.4 issue as I believe the last time we saw this may have been with a customer using PHP 7.2.

It very much points to being an issue with the GD library or extension itself.

 

[Venthas]

Is there a way to swap to using GMagick or IMagick?

 

[Chris D]

You can switch to Imagick in the global attachment options.